High voltage generator circuits are used for many different applications, including lighting applications and igniter circuits as just a few examples. In the case of igniter circuits, the voltage generated must be sufficiently high in order to cause electrical breakdown of air and create a spark. Since the breakdown voltage of air is typically 30 kV per centimeter, a voltage of several thousand volts or even tens of thousands of volts may be needed to create a spark across a gap on the order of a centimeter or less.
For most igniter circuits, the high voltage needed to create the breakdown or spark is generated from a low voltage power source, since most power sources are of relatively low voltage, on the order of tens of volts. One method of producing a high voltage from a low voltage source is to incrementally build up the high voltage on a temporary charge or voltage storing component, such as a capacitor. A switching circuit is utilized in conjunction with the voltage source and the capacitor.
A common problem associated with such switching circuits used to generate high voltage for igniter circuits is that they generate electrical noise in the circuit due to the switching involved, and since the switching involves high voltages, the voltage and/or power of the electrical noise generated is unnecessarily high. This may impact the operation of other circuitry located nearby or on the same circuit board. Additionally, the problem is especially significant when the adjacent circuitry is sensitive high speed electronic circuitry. A typical example of how to cope with this electrical noise is to physically separate the spark generator from the rest of the electronics, frequently by placing it on a different PCB, which adds cost and complexity.
Thus, there is a need for a high voltage generator circuit which is able to generate high voltage, such as that used in igniter circuits, but without causing unnecessary electrical noise or disturbance for adjacently located electronic circuitry.